The bus driver had passed out. District officials said band director Mark Linn managed to get the driver's foot off the accelerator, put on the brakes and steer the bus to safety after hitting a few construction cones.

"We are thankful the incident was not more serious and that the teacher was able to gain control of the bus to prevent a major accident," principal Jenny Marquart said in a letter to parents Thursday night.

The students were shaken up but no one was hurt. Parkway spokeswoman Cathy Kelly said many immediately used their cell phones to call their parents. The bus carried 40 students and six adults.

The bus driver had lost consciousness due to a medical condition, but was better soon after the incident. A doctor and nurse who were among Parkway parents chaperoning tended to him until paramedics arrived.

Another bus and driver were sent to the scene and the group was back on the road within a few hours. Two other buses with Parkway North students were part of the caravan headed to Florida to board a cruise ship to the Bahamas.